In the mountains, weather very quickly and every day can be different. Trekkers and mountaineers should manage their plan considering the daily weather condition. Up to date weather conditions and reports can be got along most major trekking routes. When discussing the weather in Nepal, it is important to mention that the weather can vary depending on the respective regions within Nepal. As an example, the southern areas of Nepal are typically host to fairly tropical weather, whilst, the central regions in Nepal are characterised with subtropical weather. The reasons for such differences in the weather are that Nepal is host to a significant range of altitudes within a relatively small area.

The hill, mid-hills and particularly the Kathmandu valleys are pleasant with warm summers and cool winters. Temperature ranges between maximum of 37 and minimum of 6 degree Celsius in the plains, 28 and 2 degree Celsius in the Kathmandu valley and 16 and 6 degree Celsius in the mountains. The rainy season lasts from June to August.

The climate of Nepal varies from warm summers with mild winters in the low-lying southern region, to alpine conditions with very severe winters in the mountains. Between December and February temperatures drop well below freezing in the mountains.

Nepal's climate varies with its topography and altitude. It ranges from the tropical to the arctic. The low-land Terai region with its maximum altitude to approximately 305m, which lies in the tropical southern part of the country, for instance, has a hot and humid climate that can rise above 45 Degree Celsius (113 Degree Fahrenheit) during summer.

The temperature is mildly warm in low lands while moderate in higher altitudes with plenty of opportunities to have tryst with the mountain views. It is also the time for flowers to blossom and the national flower of Nepal – rhododendron sweeps the ascending altitudes with its magnanimous color and beauty. Nepal has great variations in its climatic conditions. But the weather conditions are generally predicatable and pleasent. Spring and autumn are the most pleasant seasons in Nepal and most apt for touring the counrty.

Climatic factors are very important in deciding when to visit Nepal. October-November, the start of the dry season, is in many ways the best time of year: the weather is balmy, the air is clean, visibility is perfect, and the country is lush following the monsoon. February-April, the tail end of the dry season is the second-best period: visibility is not so good because of dust, but the weather is warm and many of Nepal's wonderful wild flowers are in bloom.

The year is divided into 4 different seasons in Nepal - winter, spring, monsoon and autumn. The best period to visit the country for plant lovers is during spring when the flowers are in full bloom. The mountain slopes are covered with beautiful and colorful flowers. Spring season commences from early March and continues until late May. Even though the days are clear haze disturbs the mountain views. Late May, and the downpour begins. It continues till late August. Come September and the autumn season begins. The climate varies considerably with elevation. May to October is monsoon season, when rain soaks the Terai and snow falls on the Himalayan peaks.In winter, average maximum and minimum temperatures in the Terai range from a brisk 7ºC (45ºF) to a mild 23ºC (74ºF). The central valleys experience a minimum temperature often falling bellow freezing point and a chilly 12ºC (54ºF) maximum. Much colder temperatures prevail at higher elevations. The Kathmandu Valley, at an altitude of 1310m (4297ft), has a mild climate, ranging from 19-27ºC (67-81ºF) in summer, and 2-20ºC (36-68ºF) in winter.